Large Knapsack

About 6g 99s on Beta · Horde (4 hours ago) and 7g 76s on Beta · Horde (22 hours ago), from player scans. A vendor pays 50s 0c, so the auction house pays 13.3× more.

No. It is in Classic Era too, with the same item level, vendor price and stack size.

Sell it on the auction house. After the 5% cut a stack of 1 brings about 6g 64s there, against 50s 0c at a vendor.